Idaho New Installation Questions, Ideas, and Justification

I'm a new member but have found this site quite useful in research. I find my self here cause I have many ideas and questions that I believe only experience and creativity can answer.

I'll start by telling everyone a short story about me, who I am, and why I am considering installing a geoexchange system. I am a 21 year old new dad, so comfort is becoming a necessity not a luxury, I purchased a home late last year, its a 2000 square foot 1 story monster on a 4 acre lot in Gooding Idaho. Half of the house is a 1915 laf and plaster, cellulose 2x4 framed farm house, the other half is a 2007ish 2x6 fiberglass insulated beauty. The current setup is a retrofit 80,000btu 80% natural gas furnace, electiric 50 gal water heater, attached to a 1950's ac pump on the verge of failure.

The ac pump got me researching because I believe the contact points on the relay are seized so the pump stays on with any power. I got several quotes and the lowest was over 4K. My goal was to replace the furnace with a 97% condensing furnace and move it closer to the newer construction so the hvac moved heat evenly throughout the hose, upgrade the water heater to a gas, and of course drop several thousand on a ac pump.

To me a geoexcahange would be a perfect solution, replace all three with one swift, the only problem is cost. I fully understand that every dollar extra I spend on my mortgage can save years and thousands. The only geoexchange company I could find within hundreds of miles was estimating $25,000. Althought when I break down the costs I believe I could do most of the work DIY and save a good deal. Which brings me to unanswered questions.

I've narrowed it down to slinky per trench, pit dig slinky, or straight pipe? I don't have a well, but I have the acreage and I believe I can get a really good price on the digging.

Should I hire someone or attempt diy on a manifold in the ground or should I run each loop into the basement where if a problem exists I can easily fix it?

I plan on running my natural gas furnace as a backup instead of expensive electric. Is this done easily with the right thermostat and some expert help.

Should I run soaker lines along the hdpe ground loop? I had a few ideas for this including using my currently wasted gray water though it, also extracting valuable energy form the flushed conditioned water. another idea was to pump dual purpose irrigation water from the channel next to my property, perhaps irragating and increasing the efficiency.

Well thats all I have right now, any thoughts and comments appreciated. Pleas no grammar Nazis English was not my favorite subject.

Manifold work requires tools and design. Inside manifold work requires different tools but gives you the ability to fix your mistakes. Depends on your skillset really which way to go. We almost never bring them inside, but we do this for a living. I find the liability of multiple foundation penetrations a bit more daunting than a buried manifold. But a homeowner/DIY can certainly weigh this risk themselves.

You have to design your loopfield for the worst conditions. You can't have it based on the fact it will get water from the soaker lines. I'd consider soaker lines iff you had dry clays that were going to pull away from buried lines. That doesn't mean don't put them in. They are just a "bonus" after the fact.

As to slinky, straight pipe, etc... - don't care. It can all be sized correctly.

Manifold work requires tools and design. Inside manifold work requires different tools but gives you the ability to fix your mistakes. Depends on your skillset really which way to go. We almost never bring them inside, but we do this for a living. I find the liability of multiple foundation penetrations a bit more daunting than a buried manifold. But a homeowner/DIY can certainly weigh this risk themselves.

You have to design your loopfield for the worst conditions. You can't have it based on the fact it will get water from the soaker lines. I'd consider soaker lines iff you had dry clays that were going to pull away from buried lines. That doesn't mean don't put them in. They are just a "bonus" after the fact.

As to slinky, straight pipe, etc... - don't care. It can all be sized correctly.

Click to expand...

I've farmed for 7 years and have collected a Pritty good amount of tools over the years. When I helped out at glabia we did some hdpe fusing on some larger diameter pipe lIke 20-30". So I do have an idea of how their fused. And as far as the foundation holes go it shouldn't be an issue.

How do I go about calculating how much liniar feet of pipe I need. The geoexchange company I mentioned above recommend 8' deep in my area at about that depth it seem to go from a soil to bb gun bb size sand for at least a few feet. I think the frost like code is 24-36 inches.

I believe they used 800' a coil and a coil per ton, but they only wanted to do a pool pit style dig. Which I have 4 acres and have read the the tight slinky configuration will compete with each other and lose efficentcy.

I'm not sure if it would be better to slinky a trench or straight pipe it. I'm kinda thinking cost would be a deciding factor their. Comets appreated.

I don't think soaker line cost to much and I think ide rather have it and not need it that the other way.

As far as tonnage is concerned (I believe hvac place wanted to install a 3 ton) as long as it's big enough to cool the house most days (115° the highest I've seen it) the heating is just a bonus. Natural gas is not very expensive here. And I'm already missing my parents wood stove.(I still go get firewood every year.)

We also have access to flood irradiation in the summer to boost efficiency when needed

Liability? Like if it don't work the pointing of fingers and all that? Well hopefully I do get some more post. I love intel I have received so far.

If I can ask one more quick question or two. Is their a such thing is over sizing a loop field, And what are the issues? Or is it just reaching a point of deminishing returns with higher instalation and pumping costs?

Can a system be designed properly undersized with a reliable sourse of heat (say natural gas) adding efficiency wile dropping installation cost onto affordable ranges. I'm set on buying a nest thermostat that offers 3 stage heat with 2 aux heat, with this can I simply install the outside thermometer into the incoming manifold, do a efficentcy to cost ratio between gas and geo, and set the thermostat to switch to gas if the heat pump/loop size can't provide valuable heat.

If I do loops in trenches with a spray pattern starting at a pvc manifold in the basement can I down the road(preferably when free or at cost digging is avalable) add a loop and/or pair a second heat pump (perhaps the same size) to meat heating/cooling needs? If pairing isn't possible/profetable a barter or sale and buy might come up with time.

Liability cuz I live in a different country and the US has a lot of courts and lawyers. Doesn't change the engineering though.

Oversizing, undersizing - always comes down to knowing the right size to begin with. Only then do you know if you're adding or subtracting. But, yes, you get diminishing returns.

You can design a system to 50% of your design load - both heat pump and ground loop. You still may cover 85% of your demand with this. There are some other considerations such as duct sizing and controls that need to be sorted, but it is a legitimate setup that can be done effectively. Easy to have a secondary fuel stage for the additional requirements at whatever design temp is required - for heating that is. You don't want to go less than your demand for cooling unless you don't need air conditioning or you want to pay for a secondary system.

If you have all the circuits accessible in your basement, then yes, it would be relatively easy to add a circuit in the future. But keep in mind things like pipe diameter and circulating pump sizing.

So could you put in a 3 ton now, knowing you need a 5 ton in the future? Yes, but you need to be careful. Your header, circulating pumps, and ducting needs to be sorted properly. At the end of the day, you'll likely be putting most things in for a full size system anyway as you probably don't want to buy another heat pump in a few years.

If I install a 5 ton system with a 3 ton loop will that cause problems with short cycling and can I counter it with a multistage compressor?

I can add my 80% 80k btu gas furnace can bring the house from a freezing 40° to Sana 80° in a few minutes and my 1980's 2.5 ton ac can still bring a chill at 100+ outside temp. If all I need is a 3 ton should I just nut up and buy a system?

As far as hvac goes the retrofit patch job the pervious owner paid for is quite frustrating dew to the furnace being so far away from the 1000 ft addition that makes up half the house. I belive moving the fernace and redoing the majority of the hvac is in order regardless. Most of it is 18" and 6" flex duct in crawlspace so I'm considering a diy experiment. How big is standard? Though I will consult with the contractor as well.

Edit: as far as manifold goes it will be short and in the basment, so expansion and upsizing should be doable, heck maybe 4" now no regrets later lol

I think the climate master web site used to have a design tool or free shareware for design help. There was another one around that cost like a 100.00 for 90 days usage. Do a search here and on the web.
Eric

When designing a geothermal heating/cooling system (any heating/cooling system for that matter), the first thing you need to know is the homes heat loss/gain characteristics to be able to accurately input that information into the calculators.

When designing a geothermal heating/cooling system (any heating/cooling system for that matter), the first thing you need to know is the homes heat loss/gain characteristics to be able to accurately input that information into the calculators.

Awesome! Much better than the endless articles I found. I did a quick Calc with estimates to try it out. I'm not sure how to upload screenshot but very useful. Thanks 5 ton man. (Haha pun intended)

I can even do load Calc for future insulation upgrade and budget their importance.

I am pretty sure I want to do the dule fuel, I mentioned above and build the system to atlast acomidate the cooling needs and over 70% of the heating needs. That way I can become more and more dependent on the heat pump as more insulation upgrades commence.

As I suspected my sistem now is a bit oversized but with no other backup and a lack of short circut I now believe it was a responsible install.

If all a get out of it is a super efficent ac for around the same 4k range as an air sourse ac pump and some cheap heat throught the spring and fall grey zones. I'll be money ahead and stay confortable.

Now Im super excited. and again thanks a million for all the feedback. Without all of your help I would have probably been overwhelmed and gave up.

***UPDATE***
So I prayed for some help in the decision and guidance with the issue, and in the next couple of days I got a flier in the mail from RightNowHeatCool.com saying they would install a 2,400 dollar high efficiency gas furnace for only 598 because business is slow right now, yatta yatta yatta. I called and found the catch, I have to buy a AC compressor at full price... But they are a local family owned business ran out of Twin Falls, Boise, and Pocatello and they did confirm that they do install water source heat pumps. So I told them I would meet with their sales tech after work Monday. I'm not totally sold on them because they don't really sale name brand pumps, and I didn't see any geoexchange information on their website. None the less im looking forword to meeting with them Monday and comparing at-least my heat loss/gain calcs.

Questions should I give a new installer a chance with heavy supervision or if their unexperienced would I be better off making newbe mistakes doing a self install.

I finished making all the measurements and did my best to fill out the load calc form what do you guys think, dose it look like I did it right.